Collection Functions - Extra functionality needed

[thygesteffensen]

https://docs.microsoft.com/en-us/azure/logic-apps/workflow-definition-language-functions-reference#item
https://docs.microsoft.com/en-us/azure/logic-apps/workflow-definition-language-functions-reference#items
https://docs.microsoft.com/en-us/azure/logic-apps/workflow-definition-language-functions-reference#iterationIndexes

These three functions need extra care, since they interact with the two loops (do until and for each).

#3 #22